As shown in FIG. 1, a conventional motor structure includes a rotor 10 centrally bundled and fixed with one end of a spindle, in which a end section 12 is formed on the other end of the spindle 11, and a reduced neck 13 with a smaller outer diameter is formed over the end section 12; a base 20 having a shaft tube 21 and a stator set 22 disposed thereon, in which the shaft tube 21 can be assembled or integrally formed on the base, the bottom end of the shaft tube 21 is sealed, an abrasive gasket 23, a washer 24, a retainer ring 25 and a bearing 25 are sequentially placed in the shaft tube 21, a positioning ring 27 is tightly fixed inside the shaft tube 21 near an opening at one end thereof so as to steadily position the bearing 26, the retainer ring 25 and so forth inside the shaft tube 21, and the stator set 22 is located on the periphery of the shaft tube 21 and is optionally in a radial winding or axial winding structure.
While the rotor 10 is assembled with the base 20, the spindle 11 of the rotor 10 penetrates through the center bore of the positioning ring 27, the bearing 26 and the retainer ring 25, and while the end section 12 of the spindle 11 urges against the retainer ring 25, an larger external force shall be applied to force the end section 12 to penetrate through the retainer ring 25 so that the retainer ring 25 snaps on the reduced neck 13 of the spindle 11 to limit an axial displacement of the spindle 11 with respect to the shaft tube 21 and to prevent the rotor 10 from dropping off.
Whereas, due to a multitude of composing members involved, the conventional motor structure has the following resulting disadvantages:
high production cost and complex assembling processes: In addition to the bearing and the positioning ring, the abrasive gasket, the washer and the retainer ring that are disposed inside the shaft tube of the conventional motor structure result in the production cost hike and complexity of the assembling process, thus coercing assembler to place the above-mentioned parts inside the shaft tube in a correct sequence within a short period of time. However, the abrasive gasket and the retainer ring all pertain to sheet-like parts and thus are easily mixed up to lead to a higher defective rate during assembling.
assembling difficulty: After the abrasive gasket and the washer is placed in the shaft tube, the retainer ring is the first in line to be assembled. However, assembling the retainer ring shall take tremendous care and the placement of the retainer ring shall be level and firm. Otherwise, the retainer ring is prone to an oblique placement inside the shaft tube as shown in FIG. 2, which makes the motor structure fail to be normally assembled.
As a consequence, to completely tackle the issue intrinsic to the above-mentioned conventional motor structure, a motor structure with a brand new idea must be aggressively conceived and developed to take both the product cost ad quality into account.